Spectrally infrared-sensitizing dyes in general are inferior in adsorption to silver halide grains, compared to spectral sensitizing dyes in the visible region, producing problems such as low sensitivity and marked reduction of sensitivity following storage. As a means for overcoming such problems, JP-A (hereinafter, the term, JP-A means an unexamined and published Japanese Patent Application) discloses a technique of using specified infrared sensitizing dyes in combination with a heteroatom containing macrocyclic compound. However, it is not only insufficient in improving effects but also concerns conventional silver halide photographic materials, and further nothing is described therein with respect to thermally developable photosensitive materials. Further, the preferred silver halide composition is taught to be silver chlorobromide. Therefore, when such techniques are applied to thermally developable silver halide photothermographic materials, problems were produced such as:
(1) insufficient prevention of desorption of sensitizing dyes from silver halide grains during storage of coated film, and PA0 (2) sensitizing dyes being easily decomposable, leading to reduced sensitivity and increased fogging. PA0 1. A silver halide photothermographic material comprising a support having thereon a light-sensitive layer and light-insensitive layer, wherein the light-sensitive layer or the light-insensitive layer comprises a heteroatom-containing macrocyclic compound, and the light-sensitive layer comprises a sensitizing dye exhibiting maximum sensitivity at a wavelength of 600 nm or more; PA0 2. The silver halide photothermographic material described in 1. above, wherein the sensitizing dye is represented by the following formula (1), (2) or (3): ##STR1## PA0 3. The silver halide photothermographic material described in 1. above, wherein the sensitizing dye represented by formula (2) is represented by the following formula (4): ##STR4## PA0 4. The silver halide photothermographic material described in 1, 2 or 3, wherein light-sensitive silver halide contains overall iodide of 0.01 to 10 mol %; PA0 5. The silver halide photothermographic material described in 1, 2, 3 or 4, wherein binder of the light-sensitive layer is mainly comprised of a polymeric latex; PA0 6. An image recording method, wherein a silver halide photothermographic material described in any one of 1 to 5 above is exposed by using a laser exposure apparatus, in which scanning laser light is not exposed at an angle substantially vertical to the exposed surface of the photothermographic material; PA0 7. The image recording method described in 6, wherein the photothermographic material is exposed by using a laser exposure apparatus, in which scanning laser light is longitudinally multiple; PA0 8. An image forming method, wherein a silver halide photothermographic material is thermally developed in a state having a moisture content of 0.01 to 5.0% by weight.
Accordingly, it is difficult to apply this technique to thermally developable photosensitive materials. Binders used in thermally developable photosensitive materials are different from those used in conventional silver halide photographic materials, and therefore adsorption of spectrally sensitizing dyes used in the thermally developable photosensitive materials are also different from the binder matrix of gelatin in conventional silver halide photographic materials. Therefore, it is necessary to apply a method suitable thereto and to realize that the technique described above is not applicable as such. Although such phenomena are marked in infrared-sensitizing dyes, similar problems are likely produced in sensitizing dyes in the visible region.
On the other hand, the need for infrared-sensitive thermally developable photosensitive materials is strong and thermally developable photosensitive materials improved in defects described above are highly desired.